PHP echo array key

Hi Experts,

How can I echo the key of a key/value pair in an array.  For example:

array([part123]=>Available [part432]=>NotAvailable [part789]=>BackOrdered)

Let's say I want to echo in HTML both the key and the value, in this case the part number and the status but in different table <td>'s.

I can do the echoing and array handling.. but I can't remember how to specifically echo the key.

Any ideas?

Thanks,

HNM